Electrically driven master clock



F. SCHNEIDER ELECTRICALLY DRIVEN MASTER CLOCK Filed Dec. 28, 1935 I l J d .l

May 17, 1938.

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.Alito-r' n 1/6' Patented May 17, 1938 UNITED 4STATES PATENT oFFicE vmmrrmcsrssr mmm cwcx licatlon December 28 ,lyeslal No 455 A zcaima (cust-s) "u, s U y may, therefore, immediately be used with second,

'I'his invention relates to electrically driven master clocks, which serve for the electrical control of secondary clocks. The contact device for closing the operating circuit for tbe electric mo- 5 tor driving the master-clock as well as the contact-device for reversing the operating current form the subject matter of separate applications for U. S. patent Ser. #56,458 and 56,457 filed by me Dec. 28, 1935, simultaneously with this application.

According to the present invention a small weighted lever is lifted and dropped every minute by the driving work of the master-clock, the weight of said lever amounting to about 1 gram. Thus only an extremely small resistance will have to be overcome by the driving work of the master-clock` in order to release the controlmechanism for the secondary clocks. As said resistance is ,represented by a constant small 20 weight which may easily be released by the driving-work of the master-clock, the latter may be regulated to keep time with the greatest degree of precision. In heretofore known master-clocks the releasing of the contacts is effected as a rule every minute by means of the second-wheel of the clock, the contact being made in many cases by means of contact-disks, contact-pins or the like mounted on the axle of the second-wheel.

Contact and release devices of this kind, how- 3Q ever, will necessarily unfavorably affect the driving organs of the clock-work and, therefore, vmust be made of very small weight preventing said devices to be made in the form of a sumciently solid and rugged mechanism able to reliably serve itsy purpose. A further disadvantage of known contact and release devices of this kind consists therein, that a minute-release cannot immediately be used without difllculties with all'kinds of clocks, such as second-clocks with second-pen- 40 dulums, three-quarter second-pendulums, halisecond pendulums, quarter-second pendulums or nnally with'works using balance-wheels. It had, therefore, .been impossible' to use one and the same contact and release organ with diiferent kinds of clockworks.

By my prese t invention the minute-release is effected by the usual wheels which serve for vdriving the hands of the clock, and more particularly by means ofthe aforementioned contact and release device which is of rugged and reliable construction. The release-wheels, moreover, are in -every case meshing with the driving-wheel for the minute-bando! the clock, said wheel being mounted on `theaxle of the minute-wheel of the clockwork. The 'same wheel-system for the hands three-quarter second, half-second or quartersecond pendulum-operated clockworks as well as with works that are operated by a balance-wheel. As the wheel for the minute-hand is mounted on the shaft to which'the driving spring is connected, the latter may be sofchosen that an undiminished driving power is always supplied to the driving-wheels of the clockwork. The swing of the pendulum will thus always be maintained at a vconstant amplitude, with the result that even with half-second-pendulum-operated clocks the time-keeping qualities will be of the highest g order. Moreover, by using a contact-device of rugged and reliable construction, there will be attained an absolutely reliable operation of the system. In my present master-clock, furthermore, the driving spring of the clockwork is rewound every minute simultaneously with the revolution of the contact-wheels by means of winding-wheels meshing with the driving-wheels, so that practically always a constant driving power is supplied to the driving-mechanism ofthe clock. According to my invention, furthermore, the contact-disk is in mesh with the motor-operated wheels of the clockwork and thus rotated simultaneously withl said wheels, while the ratio of gearing between the latter and the motor is rather high with the result that `a. relatively large contact-pressure and a reliable electrical contact is obtainable at the contact-member of the con- Y tact-disk. In consequence of this, said contactmember will be able togoperate powerful leverswitches serving to furnish the alternating current-impulses for the control of the secondary clocks. This contact-device forms the subjectmatter of a separate application for U. 8. patent ser. #56,458 illed by me simultaneously with this application'. g l

Owing to the combination of the aforementioned arrangements the master-clock willy be able toreliably operate a great number of sec-l ondary clocks connected. up in a loop with said master-clock, in a manner to attain greatest reliability and safety of operation yof the system and more particularly also in case a master-clock of the smallest type is used, for instance a quarter-second pendulum-operatedJ clock. The small electric motor will berotated every minute for a period of about two seconds figured from the moment at which the motor is started4 to the lmoment at which the motor comes to standstill in no-load condition. The small electric motor which is preferably used in connection with the present system of master-'clock forms likewise the subject matter of a special application Ser. #56,456 for U. S. patent, led by me simultaneously with this application now Pat. 2,097,134.

In the accompanying drawing which forms part of this speclilcation I have represented an exemplication of a construction of the master-clock, v

which forms part of my present invention, Fig. 1 being a iront-view of my present master-clock including a contact-device serving to operate the secondary-clocks by supplying proper currentimpulses thereto, and Fig. 2 a top-view of the clockwork of the master-clock shown in Fig. 1, said. clockwork being developed out into a plane.

Referring more particularly to thedrawing, the gear-wheel 2 for the minute-hand is mounted to rotate with proper friction about the axle of the minute-wheel of the clockwork, said wheel 2 meshing vwith the change-wheel 3-mounted rotatably in the bearing-bracket 4 fast 'on the plate I oi.' the clockwork. Mounted on the axle of said change-wheel3 is the wheel 5 meshingwith the pinion 6 of the lifting-wheel 1 carrying the lift,- ing-pins 8. `The wheel 1 is mounted rotatably between said plate I and a bearing-bracket 9 fast on said plate. A pivot I0 is fastened to the plate I (Fig. 1) and a cranked lever II, I2 is mounted swingably about said pivot I0. The free end of the horizontally directed arm I2 oi' said cranked lever ycarries a small weight I3. A further cranked lever I5, I6 is swingably mounted on another pivot I4 on the plate I, the cranked lever I5, I6 being arranged with respect to said former cranked lever II, I2 in such a manner that said weight I3 rests on the free end of the horizontally directed arm I5 of said cranked lever I5, I6. The cranked lever I5, I6 is kept under the action of :a spring I1 tending to press the horizontal arm I5 against a pin I8 fixed to the plate I. The contact levers 23, 25 y.together with the actuating lever 2l! are mounted swingably about a further pivot I9 fast on the plate I.` The actuating lever 20 carries on its free end a pin 2I by means of which said lever 20 rests on the vertical arm I6 that forms part of the cranked lever I5, I6. A spring 22 exerts a constant downward pull on said actuating lever 20. The contact springs 24 and 26 are mounted on the contact levers 23 and 25, respectively, while the actuating lever 20 is equipped with a nose 21 upwardly extending therefrom. 'I'he prolonged portion of the shaft of the main driving worm-wheel 28 carries the driving wheel 29 for the contact-device which serves to furnish the current impulses forl the operation of the secondary clocks. f

On a further pivot 30 fast on the plate iis rotatably mounted the contact-wheel 32, a bushing 3I being interposed between said'pivot and said contact-wheel. A sleeve of insulating material is placed on said bushing 3 I, said sleeve carrying a contact-cylinder 33 provided with a recessed part or incision 34, while a contact-pin 35 is mounted on the outer surface Aof said cylinder 33. I'he contact-wheel 32 is in mesh with the driving-wheel 29. The worm 38 coupled to the shaft 35 of the small electric motor 31 is in mesh with the main driving wormwheel 23, the pinion 49 on the latter being in mesh with the wheel 39, the pinion 40 of the latter with the wheel 4I and the-latter with the spring-barrel 4wheel 42.

The minute-wheel 43 meshes with the pinion 44 on the wheel 45 which forms partof the driving? the wheel 59 (Fig. l) the shaft 5I of the latter being provided with a sleeve of insulating material, said sleeve carrying the contact-disk 52 furnishing the current-impulses for operating the secondary loclm. The contact-disk 52 carries the contact-pin 53 and the two insulating pins 56 and 55. A contact-,bolt 51 is mounted within a sleeve 56 of insulating material fast on the plate Ifa current-supply spring 58 being provided on said bolt 51, the free end of said spring sliding on the periphery of said contact-disk 52.

On the plate I is further mounted an insulating plate 59, the terminals or binding-posts G0, 6I, 62, 63 and 64 being iixed to said plate 59.l Mounted rotatably about the binding-posts 60 and 6I is the contact-lever 65 and the contact-lever 6G, respectively, while the binding-post 62 is provided at its upper end with an extension carrying the contact-plate 61. The contact-levers 68 and 69 are mounted rotatably about the binding-posts 63 and 64, respectively. The free upper ends of the contact-levers 66 and 68 are provided with rollers of insulating material and kept together by action of a tension-spring 10. In like manner also the upper ends oi.' the contact-levers 65 and '69 are provid with rollers of insulating mate- 60 is connected by the lead 11 with the one electrode of the coherer-resistance 18, the other electrode of the latter being connected with said lead 14 by the lead 19. Connected to the binding-post 64 is the lead 8|! making connection with the one electrode of the coherer-resistance 81, the other electrode of the latter being connected to the lead 15 by way oi' the lead 82.

. On the plate I oi.' the clockwork there is further mounted a binding-post 84 connected by a lead 35 with the one pole of a battery 86. The other pole of said battery is connected by way of the lead 81 with the insulated binding-post 88; the latter making connection with one oi' the brushes of the small electric motor 31; the other of the brushes of said motor 31 is connected to the binding-post 89 and the latter to the contact-bolt 9| by means of the lead 99, said contact-bolt 9| being provided with a spring 92 for supplying current thereto, said spring 92 sliding on the peripheral surface of the contact-drum 33 and being further provided with a contact-pin 93. The hour-wheel 95 forming part of the train oi.' wheels for the hands of the clock is mounted rotatably on the bushing 96 oi the minute-wheel shaft forming part of said train of wheels for the hands oi' the clock and meshes with the pinion 1 of the change-wheel 3. On

. an arm 94- projecting from the running-wheel 29 there is provided a pin 98 at such a position with respect to the nose 21 on the aforesaid actuating-lever 2D that said arm 94 may co-operate with said lever 20.

A coupling-disk 99 engages laterally with the driving worm-wheel 23, said coupling-disk being carried with said worm-wheelby action of friction therebetween.

The above described system of master-clock and secondary clocks operates as follows:

Upon clockwise rotation of the minute-wheel I Iorming part of the train of wheels for the 75 of the contact-spring 28.

handsof the clock, the change-wheel 3 meshing with said minute-wheel 2 will be rotated counterclockwise so that the wheel 5 mounted on the shaft of said change-wheel 3 will likewise be rotated. By way of the pinion 6 meshing with the wheel 5 also the wheel 1 carrying the lifting-pins 8 will be rotated in clockwise sense. Upon continued rotation of the wheel 1 the arm II connected to the weighted lever I2, I3 is gradually lifted by action of said lifting-pins 8, until said arm gradually slides olf the respective lifting-pin. The arm I2 with the weight I3 thereon is thus likewise lifted at first together with lsaid arm II and thereupon falls back, so that said weight I3 will rock the arm I5 of the cranked lever I5, I8 in downward direction. During the rocking motion thus imparted to the cranked lever I5, I8 about its pivot I4 the arm I6 will turn out towards the left, so that the pin 2I which had so far been resting on said arm will slide off the latter and now .abut against the right-hand side thereof. By action of the spring 22 a powerful motion in downward direction is imparted to the actuating lever 20 swinging about the pivot I9,

thus effecting proper displacement of the contact-levers 23 and 25, with the result that the contact-spring 24 will firmly abut against the contact-pin 93 and the contact-lever 23 against the contact-cylinder 33. The point of action of the spring 22 on the actuating lever 2li is properly located with respect to its center of rotation, that is with respect to the pivot I9, to effect a strong pressure between the contacting surfaces and therewith a reliable electrical contact for the control of the secondary clocks, as only a small adhesion between the pin 2I and the arm lI6 of the cranked lever I5, I8 has to be overcome in the present case. By action of the contacts 23-33 and 24-93 anelectric circuit 84- -88-81-88-89-90-9I--92-33-23 will be closed to operate the motor 31, 23-33 representing a sliding contact and 24-93 a point-contact, the latter coming into action with a small displacement with respect to the former. Closing of the circuit for the operating current is thus accomplished in a double Way 'and in addition to this an automatic cleaning or polishing of the cooperating contact-surfaces attained. 'Ihe small motor 31 will start immediately upon being inserted into circuit, thus imparting rotation by way of its shaft 38, the worm 38 thereon and the driving worm-wheel 28 meshing with said worm 38. Rotationis thus imparted to the running-wheel 29 which is mounted on the shaft of said worm-wheel 28 together with the pin 98 on the arm 94 projecting from `said wheel 29. The running wheel meshes with the contact-wheel or disk 32 and likewise imparts rotation to the latter as well as to the contact-drum 33 mounted on the said contact-wheel or disk 32 and insulated therefrom.. Upon continued rotation the pin 35 on the contact-drum 33 will abut against the contact-lever 23 and press the latter away from said contact-drum into initial position. Simultaneously therewith the actuating arm 28 is again lifted backward until the pin 2l on said arm -20 slides along the arm I8 forming part-of the cranked locking lever I5, I8 and comes again in engagement with the latter, subsequent to the returning of said lever I5, I8 into its initial position abutting against the stop I8, by action of thespring I1. The motor 31, in spite of this, will continue to rotate, the contact-arm 25 still maintaining the motor circuit closed by action This circuit remains closed until the contact-spring 28 comes outof contact with the contact-drum 33 when dropping into the recess 34 thereof. In the meanwhile the pin 35 on the contact-drum 33, upon further rotation, has come out of the range of action of the contact-lever 23. The motor 31 operating at no-load is thereupon caused to .come to standstill by action of the pin 98 on the arm 94 projecting from the running wheel 29, said pin 98 engaging with the nose 21 on the actuating lever 20. During operation of the motor 31 the contact-wheels as well as the Winding-wheels have simultaneously been set into rotation, re-winding of the driving-spring for the driving-wheels of the clockwork having been accomplished by way of the wheels and pinions 28, 49, 39, 4l, 4I and 42. Re-winding of said spring is effected every minute, the amount of such re-winding being sufficient to keep the clock in operation until the next winding-up period.

The running gear-wheel 39 is also in mesh with the gear-wheel 50 for the contact-disk 52 insulated from its shaft, so that said gear-wheel 58 will be rotted through one half-revolution during every period of contact. By this the contactpin 53 on said contact-disk 52 will close and open, alternately with one and the other of the contact-levers 88 and 88, the circuit which serves for the control of the secondary clocks 18. 'Ihe direction of the current in this case changes as follows: v

During the first contact-period the contactpin 53 makes contact With the lever 88, thus closing the circuit 53, 88, 83, 15, 18, 14, 8|, 88, 81, 82, 13, 12, 1I, 51, 58, 52; during the second contact period the circuit 53, 88, 8|, 14, 18, 15, 83, 88, 81, 82, 13, 12, 1I, 51, 58, 52 will be established. In either case the insulating pins 54 and 55 on the contact-disk 52 will interrupt the contacts 66-61 as well as 81-88, before the contactpin 53 comes in engagement with the levers 58 and 88, for the purpose of preventing a shortcircuit from arising prior to proper closing of the circuit. The two auxiliary contact-levers 85 and 69 serve for the suppression of sparks eventually arising at the main-contacts. Said two contact-levers 85 and 89 during every contactperiod are operated first,l thus inserting into circuit in front of either main-lever one of the coherer-resistances 18 and 8|, while during interruption of the circuit the levers 85 and 89 are subsequently separated from the contact-pin 53, so that in this case also the inserted cohererresistance will come into action between the main and auxiliary contact.

I claim:

1. In a switch mechanism for master clocks and the like and which is operable by means 'of a small actuating force, the combination of a relatively iixed contact, a pivoted bell crank lever, a movable contact carried by one arm of said bell crank lever and cooperable with said xed contact for completing an electrical circuit, resilient means for moving said bell crank in a direction to close said contacts, a latch for holding said bell crank against movement by said resilient means, a weighted element, means for periodically raising said weighted element and releasing it for relatively free falling movement,

means for receiving impact of falling movement of said Weighted element and transmitting the energy therefrom to said latch to move the latter to releasing position, whereby saidbell crank lever may move to contact closing position, and means for moving said bell crank lever to contact openlng position.

2. In a switch mechanism for master clocks and the like,l the combination of a relatively Ilxed contact, a pivoted lever, a contact carried by one arm of said lever and cooperable with `said ilxed contact, resilient means for moving said lever to contact closing position, a latch for holding said lever against movement by said means, a driving m means capable of transmitting relatively small forces, means to store up energy from said drivlatter to releasing position, thereby permittingl said lever to move to contact closing position, and means to restore said lever to a. position in which said contacts are open.

FERDINAND SCHNEIDER; 

